简述氨水的物理性质。
下列关于商业网点的叙述，正确的是（） ["经济发达的腹地为商业网点的形成和发展提供了必要前提","平原的商业网点要小于山区","商业网点必须靠近商品生产地以提高商品流通的经济效益","人口稀少的地区不宜设置过密的固定商业网点"]
Gasoling fumes tend to（）. ["settle near the bottom of the blige","settle near the top of the bilge","settle evenly throughout all levels of the bilge by mixing with air","disperse to atmosphere"]
儿童保健的主要服务对象是（） ["胎儿期","新生儿期","幼儿期","婴儿期"]
下列不属于我国大城市郊区化的因素的是（） ["城市土地租金的因素","中心区危房改造与郊区新住宅区建设的加快","城市交通通信条件的改善","郊区经济的快速发展"]
简述消费者购买行为的类型。
